The present invention relates to the testing of kinetic forces and is concerned, more particularly, with the simulation of acceleration forces on projectiles and their components.
The testing of components for use in projectiles includes simulation of accelerative forces under conditions in which the forces can be accurately measured and modified to reproduce the actual forces and force changes experienced by a projectile in actual service.
For example, the ruggedness and reliability of components, such as those within an artillery fuze, generally cannot be qualitatively, quantitatively, or comparatively evaluated except under conditions which simulate flight experience.
Instead of producing the required conditions by actual flight and the consequent terminal destruction at impact, a preferred method of simulating the forces to be experienced by a projectile and its components has been through the use of an air gun accelerating a projectile to the simulated projectile muzzle speed, and then decelerating the projectile at a controlled rate to simulate the acceleration or launch setback experienced by the projectile in actual use. This deceleration has been accomplished by impacting the projectile against an opposing, deformable velocity mitigator and imparting the momentum of the projectile to a momentum exchange mass.
Examples of deformable velocity mitigators are disclosed in U.S. Pat. No. 4,010,631, issued to Pollin on Mar. 8, 1977, and incorporated by reference herein. The mitigators disclosed in this patent are preferably constructed out of honeycombed or corrugated aluminum.
At present, no laboratory controlled system is capable of providing simulation of the launch setback (acceleration-time pulse) for projectiles whose muzzle speeds exceed about 1500 feet per second. Using aluminum mitigators at speeds above 1500 feet per second presents a number of problems. The mitigators will not crush in cellular columns, nor do they maintain their structural integrity. Also, at very high projectile speeds, they may explode on impact with the projectile. Lastly, the results obtained are not reliable controllable, or reproducible. Thus, for projectile speeds in excess of 1500 feet per second, there is a need for a system which will controllably decelerate the projectile to the speeds for which aluminum mitigitors can be used.